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RESEARCH PRODUCT

Influence of Unequal Oscillator Strenghts on Stimulated Raman Adiabatic Passage through Bright State

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The problem of the coherent control of atomic states, preparation of atoms in a stable superposition state, and atomic population transfer has attracted much attention in the last decade. One of the main motivations is associated with the rapid development of the field of quantum computing. One of the key problems of quantum information processing is the construction of given coherent superposition atomic states in a macroscopic volume. Stimulated Raman adiabatic passage (STIRAP) [1] is considered to be the most common method for atomic population transfer in quantum systems. Being analyzed in detail on various quantum systems from both theoretical and experimental points of view, this method is widely adopted for the implementation of tools as optical devices for atomic beams, control of chemical reactions, high-precision magnetometry, atom cooling, etc. Meanwhile, an alternative method for population transfer, based on the intuitive pulse sequence with large one-photon detunings was demonstrated in [2]. In contrast with the STIRAP method, where the population transfer is realized via a dark state, the population transfer for the intuitive pulse sequence is obtained via a bright state. The authors of [2] called the atomic population transfer of this kind b-STIRAP. A detailed theoretical analysis of the b-STIRAP process in media with equal oscillator strength on adjacent transitions was performed in [3]. However, it is well-known that an oscillator strengths ratio different from unity can considerably impact on the coherent processes in Λ-media (see e.g. [4]). In the present work an analytical and numerical analysis of the b-STIRAP process in a medium with unequal oscillator strengths is performed. It is shown that the length of population transfer can be considerably increased by an appropriate choice of the dipole transitions. 1. N.V.Vitanov, B.W.Shore,K.Bergman, Adv. Atom.,Mol, Optical Physics, 46, 55-190, (2001). 2. J.Klein, F.Beil, Th.Halfmann, , Phys.Rev.Lett. 99,113003 (2007) 3. G.G. Grigoryan, G. Nikoghosyan, T. Halfmann, Y.T. Pashayan-Leroy, C. Leroy, S.Guerin, Phys.Rev. A 80, 033402 (2009) 4. G.G.Grigoryan, Y.Pashayan, Propagation of pulses in a three-level medium at exact two-photon resonance. Phys.Rev. A 64, 013816, 2001